1. Field of the Invention
The present invention relates to a technology of changing a tone of image data, and more particularly to an image processing apparatus, an image processing method, and a print order receiving apparatus that use the Internet.
2. Description of the Related Art
In recent years, with spread of digital cameras, it is general to save photos as digital image data. Since the digital image data can be viewed in a digital camera used for shooting or viewed in, e.g., a personal computer having the image data taken therein, how to enjoy photos has been changed. For example, there has been suggested a technology that enables converting to an image having a specific tone, e.g., a painterly tone with a different taste based on an original photo and displaying the converted image by applying image processing (snapshot to painting conversion) (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 8-44867 (corresponding to U.S. Pat. No. 5,621,868) and Jpn. Pat. Appln. KOKAI Publication No, 2004-213598).
Further, a technology that enables comparing an original image with a converted image has been also suggested (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2006-3603 (corresponding to U.S. Pat. No. 7,602,993 B2).
The snapshot-to-painting conversion is a technology that gives an arbitrary image a painterly tone by processing each pixel constituting the image in accordance with a predetermined conversion algorithm. In more detail, this technology converts an image such as a photo to an image having a tone such as an oil painting tone, a water color painting tone, an oil painting tone, a pastel tone, a color pencil drawing tone, a crayon drawing tone, an illustration tone, a pointillism tone, an air brush, a silk screen tone, a needlework painting tone, or a collage (pasting) tone.
Although the snapshot-to-painting conversion is the same as effect processing of brightening, sharpening, or softening an image in principle, the snapshot-to-painting conversion enables advanced conversion since combinations of parameters used in the effect processing are optimized in accordance with each tone which is a conversion target. That is, if there are 12 types of tones, there are prepared 12 parameter groups which are combinations of parameters.
As described above, although the snapshot-to-painting conversion enables the advanced conversion by using parameter groups prepared in accordance with a tone as a conversion target, such conversion is mainly performed for the purpose of viewing a converted image on a display screen in the conventional technology. Therefore, when printing a converted image, there occurs the following problem.
That is, in recent years, progress of the printing technology using, e.g., a printer is prominent, and a print having a reasonable tone can be obtained even if image data subjected to the snapshot-to-painting conversion is printed as it is.
However, when the image data as a display image subjected to the snapshot-to-painting conversion is printed as it is, exact texture of a painterly tone is hardly obtained. That is, when parameters for the snapshot-to-painting conversion are appropriately adjusted on the premise of a predetermined display size and a predetermined number of display pixels, there occurs a problem that appropriate adjustment of the parameter may be possibly jeopardized when image data is printed with a different size and a different number of pixels.
As one of factors of this problem, display image data consists of RGB components as three primary colors of light, whereas this data is printed with color components of YMCK at the time of printing.
Further, as another factor, image data which has been subjected to the snapshot-to-painting conversion and is displayed in the display screen and image data which has been subjected to snapshot-to-printing conversion and is to be actually printed have different numbers of pixels.